Intelligent chip placement within a three-dimensional chip stack

ABSTRACT

An integrated circuit (IC) stack device for thermal management is disclosed. The IC stack device can include a primary IC having a first set of cores with a ratio of first enabled cores and first disabled cores. The IC stack device can also have a supplementary IC interfaced with the primary IC, and having a second set of cores with a second ratio of second enabled cores and second disabled cores, with the second ratio being less than the first ratio. The integrated circuit stack device can also include a cooling element located such that the primary integrated circuit is between the cooling element and the supplementary integrated circuit. The cooling element can be designed to facilitate heat dissipation of the first and second enabled cores of the primary integrated circuit and the supplementary integrated circuit.

FIELD

This disclosure relates generally to semiconductor integrated circuitmanufacturing, and more specifically to thermal management of a 3Dintegrated circuit stack.

BACKGROUND

Integrated circuits created by semiconductor manufacturing processesoften contain defects, some of which may impact the function of theintegrated circuit. Some defects may render parts of the integratedcircuit unusable. Semiconductor manufacturers seek to improve the yieldof manufacturing processes by bypassing defective portions of integratedcircuits.

SUMMARY

Aspects of the present disclosure are directed toward an integratedcircuit stack device, and methods of using, that address challengesincluding those discussed herein, and that are applicable to a varietyof applications. These and other aspects of the present invention areexemplified in a number of implementations and applications, some ofwhich are shown in the figures and characterized in the claims sectionthat follows.

Aspects of the present disclosure, in certain embodiments, are directedtoward an integrated circuit stack device for thermal management. Incertain embodiments the integrated circuit stack device can include aprimary integrated circuit having a first set of cores with a ratio offirst enabled cores and first disabled cores. The first set of cores canbe located on a first side of the primary integrated circuit. Theprimary integrated circuit can also have a second side opposing thefirst side. In various embodiments, the integrated circuit stack devicecan also have a supplementary IC interfaced with the primary integratedcircuit. The supplementary integrated circuit can have a second set ofcores with a second ratio of second enabled cores and second disabledcores, with the second ratio being less than the first ratio. The secondset of cores can be located on a third side of the supplementaryintegrated circuit. The supplementary integrated circuit can also have afourth side opposing the third side. Consistent with variousembodiments, the integrated circuit stack device can also include acooling element located such that the primary integrated circuit isbetween the cooling element and the supplementary integrated circuit.The cooling element can be designed to facilitate heat dissipation ofthe first and second enabled cores of the primary integrated circuit andthe supplementary integrated circuit.

Aspects of the disclosure, in certain embodiments, are directed toward amethod of assembling an integrated circuit (IC) stack. In certainembodiments, the method can include testing, of a plurality of waferseach having a plurality of ICs, for factors indicative of thefunctionality of a plurality of cores located on each of the pluralityof ICs. The method can also include categorizing, as primary, a firstsubset of the plurality of wafers based on the tested factors indicatingthat ICs of the first subset are likely to have a ratio of enabled coresto disabled cores that is greater than a threshold ratio. Consistentwith various embodiments, the method can also include categorizing, assupplementary, a second subset of the plurality of wafers based on thetested factors indicating that ICs of the second subset are likely tohave a ratio of enabled cores to disabled cores that is less than thethreshold ratio. The method can also include testing of thefunctionality of the plurality of cores located on each IC of theplurality of ICs. Based on the results of the testing, a subset of theplurality of cores can be identified as having functional defects. Themethod can also include disabling the subset of the plurality of cores,in response to identifying the subset of the plurality of cores. Incertain embodiments, the method can include matching a first primary ICfrom the categorized primary wafers, with a first supplementary IC, fromthe categorized supplementary wafers. Consistent with variousembodiments, the method can include assembling an IC stack of the firstprimary IC, the first supplementary IC, and a cooling element, such thatthe primary IC is between the cooling element and the supplementary IC.The cooling element can be designed to facilitate heat dissipation ofthe enabled cores of the primary and supplementary ICs.

Aspects of the present disclosure, in certain embodiments, are directedtoward an integrated circuit stack device for thermal management. Incertain embodiments the integrated circuit stack device can include asupplementary integrated circuit having a first set of cores with firstenabled cores and first disabled cores. The first set of cores can belocated on a first side of the supplementary integrated circuit. Thesupplementary integrated circuit can also have a second side opposingthe first side. Consistent with various embodiments, the supplementaryintegrated circuit can have a first data bus. In various embodiments,the integrated circuit stack device can also have a primary integratedcircuit interfaced with the supplementary integrated circuit and havinga second set of cores with second enabled cores and second disabledcores. The second set of cores can be located on a third side of theprimary integrated circuit. The primary integrated circuit can also havea fourth side opposing the third side. Consistent with variousembodiments, the integrated circuit stack device can also include acooling element located such that the primary integrated circuit isbetween the cooling element and the supplementary integrated circuit.The cooling element can be designed to facilitate heat dissipation ofthe first and second enabled cores of the primary integrated circuit andthe supplementary integrated circuit.

The above summary is not intended to describe each illustratedembodiment or every implementation of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings included in the present application are incorporated into,and form part of, the specification. They illustrate embodiments of thepresent disclosure and, along with the description, serve to explain theprinciples of the disclosure. The drawings are only illustrative ofcertain embodiments of the invention and do not limit the disclosure.

FIG. 1 shows a three-dimensional exploded view of a primary integratedcircuit, supplementary integrated circuit, and cooling element,consistent with embodiments of the present disclosure

FIG. 2 shows a logical or functional representation of an IC stackdevice in which the functionality of disabled cores on the primaryintegrated circuit can be replaced by the functionality of enabled coreson the supplementary integrated circuit, consistent with embodiments ofthe present disclosure.

FIG. 3 shows a cross-sectional view of a primary IC and a supplementaryIC in a back-to-back orientation, consistent with embodiments of thepresent disclosure.

FIG. 4 shows a cross-sectional view of a primary IC and thesupplementary IC in a front-to-front orientation, consistent withembodiments of the present disclosure.

FIG. 5 shows a cross-sectional view of the primary IC 125 and asupplementary IC in a front-to-back orientation, consistent withembodiments of the present disclosure.

FIG. 6 shows a cross-sectional view of a primary IC and thesupplementary IC in a back-to-front orientation, consistent withembodiments of the present disclosure.

FIG. 7 shows a block diagram of the process of assembling a 3Dintegrated circuit stack device, consistent with embodiments of thepresent disclosure.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention.

DETAILED DESCRIPTION

Aspects of the present disclosure relate to various embodiments andmethods for improving yields of functional integrated circuits, moreparticular aspects relate to a 3D integrated circuit stack devicedesigned for thermal management. While the present invention is notnecessarily limited to such applications, various aspects of theinvention may be appreciated through a discussion of various examplesusing this context.

Aspects of the present disclosure relate to a 3D integrated circuitstack device designed for thermal management, with a primary IC, asupplementary IC, and a cooling element. In certain embodiments, theprimary IC has at least one non-functional core. Consistent with variousembodiments, the primary IC can be interfaced with the supplementary ICand the cooling element, such that the supplementary IC can providefunctionality from a functional core to replace that of thenon-functional core on the primary IC, and the cooling element canfacilitate heat dissipation of the IC stack device. In certainembodiments, the primary IC can be placed higher in the stack, closer tothe cooling element.

In certain instances, the primary IC's greater distance from the powersource may lead to transmitted power losses due to increased resistanceand inductance. Aspects of the present disclosure relate to therecognition that such power losses are acceptable with regard to thethermal management benefits facilitated by a configuration in which theprimary IC is placed higher in the IC stack. Accordingly, such aconfiguration can provide acceptable power capabilities with goodthermal management efficiency.

Consistent with embodiments of the present disclosure, the stacking ofprimary and supplementary ICs can be useful for improving productionefficiency. Production efficiency is pertinent to the success ofmanufacturing processes because it strongly influences the profitabilityand cost of producing manufactured goods. As a manufacturing processbecomes more efficient, the manufacturer is generally able to producegoods in less time or at a lower cost than before the efficiency gainsoccurred.

In semiconductor manufacturing, yield can refer to the fraction offunctional chips or integrated circuits produced by a manufacturingprocess. The product of a semiconductor manufacturing process may bereferred to as either a chip, a die, or an integrated circuit. A chip ordie can be a part of a silicon wafer that undergoes a manufacturingprocess to build an integrated circuit on the surface of the wafer. Awafer can be divided into pieces by a process called dicing.

An integrated circuit is a circuit where the parts of the circuit arephysically connected with each other and electrically connected.Integrated circuits built on silicon wafers can include, as part of thecircuit, areas of the wafer surface that have been modified to havespecific electrical properties. Other parts of the circuit can be builtatop this treated wafer surface as layers of materials are added to thewafer surface. Because these added-on components of the circuit(contacts, trenches, vias, conducting materials, insulating materials,liners, etc. . . . ) are part of (or integrated within) the wafersurface, the term integrated circuit can also refer to the chip or diethat contains the integrated circuit.

Integrated circuits can be designed with one or more functional blocks,also referred to herein as cores. Each core can be physically located ina respective region of an integrated circuit, and can perform anintended function in the greater integrated circuit. A core can containa circuit block that actually performs the intended function as well ascircuitry that communicates data into and out of the circuit block. Acore may also contain additional circuit elements that optionallydisable the circuit block. Many modern integrated circuits containmultiple cores of different types, including such types as centralprocessing units (CPUs), graphical processing units (GPUs), memorymanagement units (MMUs), memory controllers, input/output controllers,optical sensors, and other specialty digital and analog circuitcomponents.

As semiconductor technology has advanced, the structural features ofintegrated circuits have become extremely small. Semiconductor gatestructures with lateral measurements smaller than 30 nanometers can beproduced in certain manufacturing facilities, and film thicknesses assmall as a few Angstroms are possible. While these small dimensions maynot be found throughout the semiconductor device, scaling certain partsof integrated circuits can be useful for achieving small die sizes thatwill fit more chips on a wafer.

The structure and chemical composition of a circuit's structuralelements dictate the circuit's function. If either the structure orchemical composition is sufficiently disrupted, the integrated circuitmay not function as intended and the circuit may need to be discarded orrepaired. The small size of individual structural elements in anintegrated circuit makes them very fragile and susceptible to damagethat may disrupt the integrated circuit's function. Such damage may belocalized or widespread, potentially rendering a circuit block, a core,or an entire integrated circuit nonfunctional. The level offunctionality acceptable for a core or a functional block can varydepending on the application and purpose of the integrated circuit. Forexample, an integrated circuit intended for use as part of a memorymanagement system may have a different acceptable functionalitythreshold for cores than an integrated circuit intended for use as partof a graphical processing unit. Cores that are found to be below thefunctionality threshold desired for a particular application can beconsidered non-functional.

Integrated circuit defects may occur via chemical contamination,processing errors, electrostatic discharge, or the introduction ofparticles into the circuit so as to disrupt the electricalcharacteristics of properly formed circuit structural elements or todisrupt the physical structure of the circuit itself, interfering withthe circuit's proper electrical function. For example, chemicalcontamination may disrupt the electrical performance of a gate structurecreating a short in the circuit. Alternatively, when the chemicalcomposition of photo-resist is altered, the resist may not develop ordissolve properly, causing disruption or destruction of the intendedpattern on the silicon wafer. Electrostatic discharge during filmdeposition or etching can melt deposited metal, break insulatingbarriers, and scatter particles across the wafer surface that bridgeconductive areas or block conductive lines. Processing errors may resultin incomplete etching, leaving, for example, material at the bottom ofvia structures that blocks the intended conductive path through aninsulating dielectric layer. Also, particulate contamination can blocketches, fill and break conductive lines, and knock over delicate gatestructures.

These and other types of defects can be reduced by identifying andeliminating the sources of individual defects in order to increase totalchip yield. For instance, sources of particulate contamination can beidentified and eliminated. Wafer processing steps can also be frequentlyadjusted to address chemical contamination or processing errors. Thesources of the largest particulate contaminants can be the easiest toeliminate and the first ones selected for removal because largeparticles affect larger areas of the integrated circuit. Identifying andeliminating the sources of smaller, more widespread particles can be amore difficult exercise than for large particles, but may neverthelessbe undertaken if the smaller particles cause sufficient harm to thefinal integrated circuits. Chemical contamination and electrostaticdischarge damage may be identified by special analytical methods beforethe manufacturing process can be changed. In some circumstances, in situdefect reduction may not be a cost effective way to completely eliminateyield problems, requiring additional steps to improve yield.

One method of overcoming persistent defects in integrated circuits is todesign redundancy into the overall integrated circuit by placingadditional cores in the chip. When a manufacturing process is complete,the manufacturer can test the chips for function and partition themaccording to their defect rate or performance. Fully functional chips,or at least sufficiently functional chips, can be sold or distributedwithout further treatment, while chips that have defective cores can besubject to an in situ repair process, where defective cores are disabledor bypassed and functional redundant cores are enabled to provide theintended number of cores in the final integrated circuit product.Alternatively, a sufficient number of defective and functional cores maybe disabled, providing a lesser number of cores that will still allowfor operation of the integrated circuit at a lower performance levelthan originally planned for the circuit. The use of redundant cores toovercome core-damaging defects can add additional costs, whether interms of physical space on the chip or manufacturing costs. Forinstance, designs with redundant cores can use additional wafer surfacearea per chip and decrease the number of chips that fit on a singlewafer. With fewer chips available per wafer, a manufacturer may end uphaving to produce more wafers to achieve a target number of functionalchips.

An alternative method of overcoming core-damaging defects is to performan ex situ repair process on defective chips by stacking two same-typechips on top of each other and electrically connecting parts of the twointegrated circuits together. Consistent with embodiments of the presentdisclosure, defective chips from a single manufacturing process can beused to repair each other by identifying and isolating good cores in asupplemental chip, deactivating bad cores in a primary chip, and linkingthe supplemental chip's good cores into the primary chip integratedcircuit. When ex situ repair is successful, the repaired primary chipcan perform its intended function and increases overall manufacturingyield. Ex situ stacked chip repair can allow manufacturers to repairintegrated circuits without the need for redundant cores, therebyreducing the size of each IC and making it possible to fit more chips ona wafer.

Aspects of the present disclosure are directed toward challenges relatedto 3D chip stacks, such as providing sufficient thermal management. Ascomputing requirements increase, so too do the processing speeds andclock frequencies of integrated circuits, which can result in anincrease in power consumption. Similarly, this increase in powerconsumption can lead to greater heat output. It can be desirable forintegrated circuits to be maintained within a specified temperaturerange in order to avoid overheating, instability, and component damage,which can lead to a shortened integrated circuit lifespan. Facilitatingadequate cooling for multiple circuit layers can be more challengingthan for a single integrated circuit, as the heat generated by eachintegrated circuit accumulates, resulting in a higher temperaturegradient for the chip stack. Moreover, as the stack size increases, thedistance between the active components and a heat dissipation point canincrease, leading to a reduced cooling efficiency.

Vertically oriented chip stacks can include a primary IC and asupplementary IC, the primary IC having a higher number of functionalcores than the supplementary IC, and the supplementary IC interfacedwith the primary IC to provide replacement cores for those that havebeen disabled on the primary IC. Additionally, a cooling element canalso be included in the chip stack to facilitate heat dissipation. Asthe primary IC can have greater power requirements than thesupplementary IC due to its greater number of functioning cores, itsplacement lower in the chip stack results in the primary IC beinglocated proximate to the power source. This can be useful for reducingtransmission losses (e.g., due to increased resistance or inductance).

Embodiments of the present disclosure relate to the recognition thatfrom a thermal management perspective, lower placement of the primary ICcan result in a significant heat generator—the primary IC—being locatedfarther from the cooling element. For instance, placing the primary IClower in the IC stack can lead to the generation of excess heat andresult in higher temperature gradients for the IC stack, leading toimpaired processing efficiency, decreased stability, and shortenedcomponent life spans. Accordingly, aspects of the present disclosurerelate to a stacking configuration which can be particularly useful formitigating excess heat, and improving the overall efficiency, stability,and lifespan of the IC stack components.

Aspects of the present disclosure relate to a 3D integrated circuitstack device designed for thermal management and heat distribution. Forinstance, embodiments of the present disclosure are directed toward a 3Dintegrated circuit stack in which a primary IC having one or morenon-functional cores can be interfaced with a cooling element and with asupplementary IC to provide replacement cores, such that the primary ICcan be located between the supplementary IC and the cooling element.Consistent with various embodiments, the primary IC and thesupplementary IC can both be full-size die. In certain embodiments, theprimary IC and the supplementary IC can be arranged in a front-to-frontstacking configuration. In certain embodiments, the primary IC and thesupplementary IC can be arranged in a front-to-back stackingconfiguration. In certain embodiments, the primary IC and thesupplementary IC can be arranged in a back-to-back stackingconfiguration.

Consistent with various embodiments, the primary IC can have a first setof cores, including enabled cores and disabled cores, located on asurface of the primary IC. Similarly, the supplementary IC can have asecond set of cores, including enabled cores and disabled cores, locatedon a surface of the supplementary IC. The first set of cores and thesecond set of cores can include a variety of types of circuitcomponents, such as central processing units (CPUs), graphicalprocessing units (GPUs), memory management units (MMUs), memorycontrollers, input/output controllers, optical sensors, and otherspecialty digital and analog circuit components.

Consistent with various embodiments, the cooling element can be anactive or passive component capable of facilitating heat dissipation ofthe IC stack. For example, in certain embodiments, the cooling elementcan include one or more passive cooling components such as a heat sink.In certain embodiments, the cooling element can include one or moreactive cooling components such as a fan or liquid cooling deliverysystem or device.

Consistent with various embodiments, the primary IC and thesupplementary IC can be equipped with on-chip communication networks,enabling a variety of connections to other components such as otherchips in the IC stack, devices external to the IC stack, and powersupplies. Further, the primary IC and the secondary IC can each includea data bus that allows for communication between cores located on arespective integrated circuit. Once integrated circuits have beendesignated as primary ICs and supplementary ICs in the manufacturingprocess, the IC stack device can be connected and configured such thatthe data bus on the primary IC functions as an active data bus for allcores on both the primary IC and the supplementary IC. For example, incertain embodiments, the data bus on the primary IC can be utilized tofacilitate the routing of information between the cores on one chip inthe IC stack and cores on other chips in the IC stack.

In various embodiments, the communication networks of the primary IC andthe supplementary IC can include on-chip logical elements to replace thefunctionality of disabled cores on the primary IC with enabled coresfrom the supplementary IC. In certain embodiments, the logical elementscan include a multiplexer block configured to route communicationbetween a core on an IC and one or more data buses that can be connectedto other cores, thereby allowing communication between cores. In certainembodiments, the multiplexer block can be configured to selectivelyroute signals between the data bus on the primary IC and cores on eitherthe primary IC or the supplementary IC. The signal selection can bebased upon the functional state of the cores. For instance, in certainembodiments, an enabled core on the supplementary IC can sendcommunication signals through the multiplexer block on the primary IC,which can route these signals to the data bus in place of the signalfrom a disabled core on the primary IC. Control signals for themultiplexer blocks (e.g., signals to control the activation ordeactivation of cores) can be sent from the respective IC on which themultiplexer block is located.

In certain embodiments, the primary IC and the supplementary IC can bearranged in a variety of configurations. Integrated circuits have twosurfaces that are pertinent to describing certain configurationsmentioned in the present disclosure: an active device surface on whichthe components critical to the IC's function are located, and a diesubstrate surface opposing the active device surface. Consistent withvarious embodiments, the primary IC and the supplementary IC can bearranged such that the active device surface (front) of the primary ICcan be interfaced with the front of the supplementary IC. In certainembodiments, the primary IC and the supplementary IC can be arrangedsuch that the front of the primary IC can be interfaced with the diesubstrate surface (back) of the supplementary IC. Further, in certainembodiments, the primary IC and the supplementary IC can be arrangedsuch that the back of the primary IC can be interfaced with the front ofthe supplementary IC. In certain embodiments, the primary IC and thesupplementary IC can be arranged such that the back of the primary ICcan be interfaced with the back of the supplementary IC. Accordingly,the orientation of the primary IC and the supplementary IC can be variedto meet the needs of a variety of applications.

In various embodiments, the orientation of the primary IC and thesupplementary IC may result in cores of the supplementary IC beinglocated at a greater distance from the primary data bus. For instance,consistent with various embodiments, the primary IC and thesupplementary IC may be oriented in a front-to-back stackingconfiguration, in which case the die substrate layer of one of the chipsmay separate the primary data bus from the cores of the supplementaryIC. Accordingly, aspects of the present disclosure are directed toward a3D IC stack device that includes one or more through-silicon vias (TSVs)that enable power delivery and communication between the primary IC andthe supplementary IC in a variety of stacking configurations. Forinstance, in certain embodiments, the signal from one or more functionalcores on the supplementary IC can be carried by a TSV connection to themultiplexer block on the primary IC. Such configurations can beparticularly useful when the primary IC and the supplementary IC areoriented in a front-to-back or back-to-back stacking configuration.

In certain embodiments, power is supplied to the IC stack device via apower source located below the cooling element, primary IC, andsupplementary IC in the IC stack. In certain embodiments, power can bedelivered to the IC stack by one or more TSVs. For example, in certainembodiments, a TSV can carry power from a power source through or fromthe supplementary IC to the primary IC.

Consistent with various embodiments, during the IC fabrication process,silicon wafers and individual die (e.g. die that have passed through thedicing operation) can undergo a back-grinding process to reduce thethickness of the die substrate layer. Such a process can facilitatepower delivery to chips in an IC stack, as well as having positiveeffects on the IC stack's thermal balance. For instance, back grindingtechniques can decrease the distance between a power source and theactive device layer of a chip in an IC stack, reducing inductance andresistance while mitigating associated losses in transmitted power.Further, the use of back grinding techniques to reduce the thickness ofthe die substrate layer can decrease the distance between a chip in anIC stack and a cooling element, facilitating heat dissipation of the ICstack.

Turning now to the figures, FIG. 1 shows a three-dimensional explodedview of the primary integrated circuit 125, supplementary integratedcircuit 150, and cooling element 100, consistent with embodiments of thepresent disclosure. Aspects of FIG. 1 are directed toward a 3Dintegrated circuit stack device designed for thermal management, andincluding a primary IC 125 that can be located between a supplementaryIC 150 and a cooling element 100. The primary IC 125 can be interfacedwith the supplementary IC 150 and the cooling element 100 such that thecooling element can facilitate heat dissipation of the IC stack device.Consistent with various embodiments, the primary IC 125 can include afirst set of cores including one or more functional cores (depictedwithout shading) and one or more non-functional cores (depicted asshaded), such as non-functional core 104, located on a surface of theprimary IC 125. Similarly, the supplementary IC 150 can include a secondset of cores including one or more functional cores, such as functionalcore 102, and one or more non-functional cores, located on a surface ofthe supplementary IC 150. In certain embodiments, functional cores canbe disabled to facilitate thermal and power management of the IC chipstack.

Consistent with various embodiments, the primary IC 125 and thesupplementary IC 150 can each include a data bus configured to routeinformation between cores located on a respective integrated circuit. Incertain embodiments, once an IC has been designated as a primary IC 125in the manufacturing process, the IC stack device can be connected andconfigured such that the data bus 108 on the primary IC 125 can functionas an active data bus for all cores on both the primary IC 125 and thesupplementary IC 150. In certain embodiments, the data bus 106 on thesupplementary IC can be capable of facilitating communication betweenthe cores on the supplementary IC. In certain embodiments, the data bus106 can be inactive.

FIG. 2 shows a logical or functional representation of the system inwhich the functionality of non-functional cores (depicted as shaded) onthe primary integrated circuit 125 can be replaced by the functionalityof functional cores (depicted without shading) on the supplementaryintegrated circuit 150. Aspects of FIG. 2 are directed toward systemsand methods designed to increase the yield of functional integratedcircuits. Consistent with various embodiments, FIG. 2 shows a logical orfunctional representation of both a primary IC 125 and a supplementaryIC 150, which can each include a number of functional cores, such asfunctional core 102 and non-functional cores, such as non-functionalcore 104. As discussed herein, in certain embodiments, the primary IC125 can have more functional cores than the supplementary IC 150.

In certain embodiments, the 3D IC stack device can be designed to allowthe functionality of functional cores on the supplementary IC 150 to beutilized in place of non-functional cores on the primary IC 125, therebyreplacing the functionality of the non-functional core (which may bedisabled). For example, consistent with various embodiments, thefunctionality of the functional core 102 can be utilized in place of thefunctionality of the non-functional core 104. By replacing thefunctionality of non-functional cores on the primary IC 125 with thefunctionality of functional cores on the supplementary IC, the IC stackdevice can make use of a greater number of cores than either the primaryIC 125 or the supplementary IC 150 individually, as depicted by theresultant IC logical or functional representation 300.

Consistent with various embodiments, the primary IC 125 and thesupplementary IC 150 can be matched such that the supplementary IC 150has functional cores in locations that correspond to the locations ofthe non-functional cores on the primary IC 150. This configuration canbe particularly useful for facilitating communication between theprimary IC and the supplementary IC. Further, in certain embodiments,there can be a 1:1 ratio between the non-functional cores on the primaryIC and the functional cores on the supplementary IC 150.

In certain embodiments, the supplementary IC 150 can have a greaternumber of functional cores than the number of non-functional cores onthe primary IC 125. In such a configuration, the extra functional coreson the supplementary IC 150 can be treated as “spare cores,” and can beutilized to supplement the primary IC 125, or for redundancy, e.g., as areplacement in case of core failure on the primary IC 125. In certainembodiments, these “spare cores” can be disabled (e.g. physicallydisabled with a fuse, or logically disabled, such as through the use ofan EPROM logic switch) until they are desired as a replacement core, atwhich point they can be re-activated. Further, in certain embodiments,these spare cores can be activated in order to balance the thermaldistribution of the active cores within the IC stack without adverselyimpacting performance. For example, consistent with various embodiments,a functional core on the primary IC 125 can be temporarily disabled, anda spare core on the supplementary IC 150 can be utilized instead,shifting the heat generation to elsewhere in the IC stack, and havingpositive effects on the overall thermal distribution of the IC stackdevice.

Aspects of the present disclosure relate to the recognition that, incertain embodiments, the supplementary IC 150 can have a lesser numberof functional cores than the number of non-functional cores on theprimary IC 125. In certain embodiments, certain cores within primary IC125 may have been designed with functionality similar to or redundantwith another core in the IC stack, such that one of them is sufficient.Further, consistent with various embodiments, one or more cores on thesupplementary IC 150 can be specifically designed to have functionalityredundant with a non-functional core on the primary IC 125, and thus actas a replacement. In certain embodiments, the application of the ICcircuit stack may allow for a lesser number of total functional cores,such that some number of non-functional cores can be consideredacceptable. For example, in certain embodiments, the resultant ICrepresentation 300 can have 10 functional cores. In certain embodiments,the resultant IC representation 300 can have 7 functional cores. Othercore configurations are also possible. Such configurations can havepositive effects on manufacturing productivity, and allow for thecreation of lower cost products.

FIG. 3 shows a cross-sectional view of the primary IC 125 and thesupplementary IC 150 in a back-to-back orientation. Consistent withcertain embodiments, functional core 102 can be enabled, andnon-functional core 104 can be disabled. For ease of discussion withreference to FIGS. 3-5, these cores can be referred to as enabled core102 and disabled core 104, respectively. Aspects of FIG. 3 are directedtoward a 3D IC stack device with an on-chip communication network andlogic system configured to replace the functionality of a disabled core104 on a primary IC 125 with the functionality of an enabled core 102from a supplementary IC 150. In certain embodiments, the primary IC 125and the supplementary IC 150 can be arranged in a back-to-backconfiguration, in which the die substrate surfaces of each IC areinterfaced with one another.

Consistent with various embodiments, the primary IC 125 and thesupplementary IC 150 can be arranged in a back-to-back configuration, inwhich the die substrate surfaces of each IC are interfaced with oneanother. Further, in certain embodiments, the primary IC 125 and thesupplementary IC 150 can have identical active device layer layouts(i.e. active devices of the same size and type located in the samerespective location of each IC). Aspects of the present disclosurerelate to the recognition that, in such a configuration (i.e.,back-to-back and with identical active device layer layouts), theprimary IC 125 and the supplementary IC 150 are inverted with respect toone another. This can cause misalignment between active devices (e.g.cores, input/output rings, communication contacts, power pins) on theprimary IC 125 with corresponding active devices on the supplementary IC150. Accordingly, to facilitate alignment between the active devices onthe primary IC 125 with corresponding active devices on thesupplementary IC 150, aspects of the present disclosure relate todesigning a primary IC 125 and a supplementary IC 150 with symmetryrelative to one another about the horizontal or vertical axis of theactive device surface. Such a symmetry condition can allow the activedevices on the primary IC 125 to align properly with correspondingactive devices on the supplementary IC 150 in a back-to-backconfiguration.

In certain embodiments, the primary IC 125 and the supplementary IC 150can be composed of a plurality of layers, including but not necessarilylimited to one or more of the following: a die substrate layer 220, 240,a front-end-of-line (FEOL) layer 218, 242, a (critical logic)back-end-of-line (BEOL) layer 214, 244, a partition/global BEOL layer212, and a custom BEOL layer 246. In certain embodiments, after beingdesignated as a supplementary IC in the manufacturing process, thesupplementary IC 150 can be equipped with a custom BEOL layer 246designed to facilitate connectivity between the supplementary IC 150 andthe primary IC 125. Consistent with various embodiments, the diesubstrate layer 220, 240, FEOL layer 218, 242, (critical logic) BEOLlayer 214, 244, partition/global BEOL layer 212, and custom BEOL layer246 can each be made up of one or more sub-layers of semiconductormaterials, interconnection devices, or other structures.

Aspects of the present disclosure relate to a 3D IC stack device with aprimary IC 125 and a supplementary IC 150 arranged in a back-to-backorientation. In such a configuration, with the die substrate surface 220of the primary IC 125 interfaced with the die substrate surface 240 ofthe supplementary IC 150, the partition/global BEOL layer 212 of theprimary IC 125 can be directly interfaced with a cooling element,facilitating heat dissipation of the active devices on the primary IC125. As these active devices can be a significant source of heatgeneration in the IC chip stack, such a back-to-back configuration canhave positive effects on the thermal management of the IC chip stack.

Aspects of the present disclosure are directed toward a 3D integratedcircuit stack device including one or more multiplexer blocks configuredto selectively route data between cores in the IC stack and a variety ofperipheral components, such as an input/output ring or a data pin. Otherperipheral components are also possible. In certain embodiments, boththe primary IC 125 and the supplementary IC 150 can include amultiplexer block. In certain embodiments, the multiplexer block 224 onthe supplementary IC 150 can be unused, and the multiplexer block 210 onthe primary IC can function as the active multiplexer block for the ICstack device. For instance, in certain embodiments, the multiplexerblock 210 can be communicatively connected with an enabled core 102 onthe supplementary IC and a disabled core 104 on the primary IC. Themultiplexer block 210 can then selectively route data from the enabledcore 102 to a data bus in place of data from the disabled core 104.

Consistent with various embodiments, the primary IC 125 and thesupplementary IC 150 can include one or more TSV connections to allowfor communication between the supplementary IC 150 and the primary IC125. In certain embodiments, the primary IC 125 can include a TSV 202and a TSV 206, and the supplementary IC 150 can include a TSV 204 and aTSV 208. The TSV 202 and the TSV 206 can be connected to the TSV 204 andthe TSV 208, respectively, by means of a first chip interconnect 230 anda second chip interconnect 232. The chip interconnects can follow one ormore of a variety of chip interconnect designs, including but notnecessarily limited to a solder bump, a pogo pin, or a fuzzy bump. Incertain embodiments, the multiplexer block 210 can be connected to theenabled core 102 through the TSV 206, the second chip interconnect 232,and the TSV 208. In certain embodiments, the multiplexer block 210 canconnect to a peripheral component connection 228 (e.g., an input/outputring or a data pin) through the TSV 202, the first chip interconnect230, and the TSV 204.

FIG. 4 shows a cross-sectional view of the primary IC 125 and thesupplementary IC 150 in a front-to-front orientation. Aspects of FIG. 4are directed toward a 3D IC stack device with an on-chip communicationnetwork and logic system configured to replace the functionality of adisabled or non-functional core 104 on a primary IC 125 with thefunctionality of an enabled core 102 from a supplementary IC 150. Incertain embodiments, the primary IC 125 and the supplementary IC 150 canbe arranged in a front-to-front configuration, in which the activedevice surfaces of each IC are interfaced with one another.

Consistent with various embodiments, the primary IC 125 and thesupplementary IC 150 can be arranged in a front-to-front configuration,in which the die substrate surfaces of each IC are interfaced with oneanother. Further, in certain embodiments, the primary IC 125 and thesupplementary IC 150 can have identical active device layer layouts(i.e. active devices of the same size and type located in the samerespective location of each IC). Aspects of the present disclosurerelate to the recognition that, in such a configuration (i.e.,front-to-front and with identical active device layer layouts), theprimary IC 125 and the supplementary IC 150 are inverted with respect toone another. This can cause misalignment between active devices (e.g.cores, input/output rings, communication contacts, power pins) on theprimary IC 125 with corresponding active devices on the supplementary IC150. Accordingly, to facilitate alignment between the active devices onthe primary IC 125 with corresponding active devices on thesupplementary IC 150, aspects of the present disclosure relate todesigning a primary IC 125 and a supplementary IC 150 with symmetryrelative to one another about the horizontal or vertical axis of theactive device surface. Such a symmetry condition can allow the activedevices on the primary IC 125 to align properly with correspondingactive devices on the supplementary IC 150 in a front-to-frontconfiguration.

In certain embodiments, the primary IC 125 and the supplementary IC 150can be composed of a plurality of layers, including but not necessarilylimited to one or more of the following: a die substrate layer 220, 240,a front-end-of-line (FEOL) layer 218, 242, a (critical logic)back-end-of-line (BEOL) layer 214, 244, a partition/global BEOL layer212, and a custom BEOL layer 246. In certain embodiments, after beingdesignated as a supplementary IC in the manufacturing process, thesupplementary IC 150 can be equipped with a custom BEOL layer 246designed to facilitate connectivity between the supplementary IC 150 andthe primary IC 125. Consistent with various embodiments, the diesubstrate layer 220, 240, FEOL layer 218, 242, (critical logic) BEOLlayer 214, 244, partition/global BEOL layer 212, and custom BEOL layer246 can each be made up of one or more sub-layers of semiconductormaterials, interconnection devices, or other structures.

Aspects of the present disclosure relate to a 3D IC stack device with aprimary IC 125 and a supplementary IC 150 arranged in a front-to-frontorientation. In such a configuration, with the partition/global BEOLlayer 212 of the primary IC 125 interfaced with the custom BEOL layer ofthe supplementary IC 150, few (if any) TSVs are needed to connect theprimary IC 125 and the supplementary IC 150, reducing the overallcomplexity and number of components of the IC stack device. As thefront-to-front orientation allows for proximate connection between theactive device layer of the primary IC 125 and the supplementary IC 150,such a configuration can be particularly useful for facilitatingcommunication between the integrated circuits in the IC stack. Forinstance, high speed data signals may be subject to restrictions onsignal path length, capacitive loading and other parameters that can bemitigated with shorter signal connection paths.

Aspects of the present disclosure are directed toward a 3D integratedcircuit stack device including one or more multiplexer blocks configuredto selectively route data between cores in the IC stack and a variety ofperipheral devices, such as an input/output ring, a power source, or adata pin. Other peripheral devices are also possible. In certainembodiments, both the primary IC 125 and the supplementary IC 150 caninclude a multiplexer block. In certain embodiments, the multiplexerblock 224 on the supplementary IC 150 can be unused, and the multiplexerblock 210 on the primary IC can function as the active multiplexer blockfor the IC stack device. For instance, in certain embodiments, themultiplexer block 210 can be communicatively connected with an enabledcore 102 on the supplementary IC and a disabled core 104 on the primaryIC 125, and selectively route data from the enabled core 102 to a databus in place of data from the disabled core 104.

Consistent with various embodiments, the supplementary IC 150 can haveone or more TSV connections that allow for communication between one ormore ICs in the chip stack and devices external to the chip stack, aswell as between the supplementary IC 150 and the primary IC 125. Forexample, in certain embodiments, the supplementary IC 150 can include aTSV 204 that provides an electrical connection between the multiplexerblock 210 and a peripheral device connection 228. The TSV 204 can beelectrically connected to the primary IC 125 through the use of a chipinterconnection 230. In certain embodiments, the multiplexer block 210on the primary IC can be connected to the enabled core 102 through thechip interconnection 232. The chip interconnects can follow one or moreof a variety of chip interconnect designs, including but not necessarilylimited to a solder bump, a pogo pin, or a fuzzy bump. In certainembodiments, the multiplexor block 210 can be communicatively connectedwith an input/output ring on the primary IC 125 or the supplementary IC150 that can facilitate connection to devices external to the IC stackthrough a TSV connection.

FIG. 5 shows a cross-sectional view of the primary IC 125 and thesupplementary IC 150 in a front-to-back orientation. Aspects of FIG. 5are directed toward a 3D IC stack device with an on-chip communicationnetwork and logic system configured to replace the functionality of adisabled or non-functional core 104 on a primary IC 125 with thefunctionality of an enabled core 102 on a supplementary IC 150. Incertain embodiments, the primary IC 125 and the supplementary IC 150 canbe arranged in a front-to-back configuration, in which the active devicesurface of the primary IC 125 is interfaced with the die substratesurface of the supplementary IC 150.

In certain embodiments, the primary IC 125 and the supplementary IC 150can be composed of a plurality of layers, including but not necessarilylimited to one or more of the following: a die substrate layer 220, 240,a front-end-of-line (FEOL) layer 218, 242, a (critical logic)back-end-of-line (BEOL) layer 214, 244, a partition/global BEOL layer212, and a custom BEOL layer 246. In certain embodiments, after beingdesignated as a supplementary IC in the manufacturing process, thesupplementary IC 150 can be equipped with a custom BEOL layer 246designed to facilitate connectivity between the supplementary IC 150 andthe primary IC 125. Consistent with various embodiments, the diesubstrate layer 220, 240, FEOL layer 218, 242, (critical logic) BEOLlayer 214, 244, partition/global BEOL layer 212, and custom BEOL layer246 can each be made up of one or more sub-layers of semiconductormaterials, interconnection devices, or other structures.

Aspects of the present disclosure relate to a 3D IC stack device with aprimary IC 125 and a supplementary IC 150 arranged in a front-to-backorientation. In such a configuration, with the partition/global BEOLlayer 212 of the primary IC 125 interfaced with the die substratesurface of the supplementary IC 150, power from a power source below thesupplementary IC 150 can be delivered to the active device layer of theprimary IC 125 without passing through the die substrate layer 220 ofthe primary IC 125. Such a configuration can be particularly useful forfacilitating power delivery to the primary IC 125, and can reduceinductance and resistance while mitigating associated losses intransmitted power.

Aspects of the present disclosure are directed toward a 3D integratedcircuit stack device including one or more multiplexer blocks configuredto selectively route data between cores in the IC stack and a variety ofperipheral devices, such as an input/output ring, a power source, or adata bus. Other peripheral devices are also possible. In certainembodiments, both the primary IC 125 and the supplementary IC 150 caninclude a multiplexer block. In certain embodiments, the multiplexerblock 224 on the supplementary IC 150 can be unused, and the multiplexerblock 210 on the primary IC can function as the active multiplexer blockfor the IC stack device. For instance, in certain embodiments, themultiplexer block 210 can be communicatively connected with an enabledcore 102 on the supplementary IC and a disabled core 104 on the primaryIC 125, and selectively route data from the enabled core 102 to a databus in place of data from the disabled core 104. In certain embodiments,the multiplexor block 210 can be communicatively connected to aninput/output ring or other communication elements through a TSVconnection.

Consistent with various embodiments, the supplementary IC 150 caninclude one or more TSV connections to allow for communication betweenthe supplementary IC 150 and the primary IC 125. In certain embodiments,the supplementary IC 150 can include a TSV 204 and a TSV 208. The TSV204 and the TSV 208 can be connected to the primary IC 125 through theuse of a first chip interconnect 230 and a second chip interconnect 232,respectively. In certain embodiments, the multiplexer block 210 can beconnected to the enabled core 102 through the second chip interconnect232 and the TSV 208. In certain embodiments, the multiplexer block 210can connect to a peripheral component connection 228 (e.g., aninput/output ring or a data pin) through the first chip interconnect 230and the TSV 204.

FIG. 6 shows a cross-sectional view of the primary IC 125 and thesupplementary IC 150 in a back-to-front orientation. Aspects of FIG. 6are directed toward a 3D IC stack device with an on-chip communicationnetwork and logic system configured to replace the functionality of adisabled or non-functional core 104 on a primary IC 125 with thefunctionality of an enabled core 102 from a supplementary IC 150. Incertain embodiments, the primary IC 125 and the supplementary IC 150 canbe arranged in a back-to-front configuration, in which the die substratesurface of the primary IC 125 is interfaced with the active devicesurface of the supplementary IC 150.

In certain embodiments, the primary IC 125 and the supplementary IC 150can be composed of a plurality of layers, including but not necessarilylimited to one or more of the following: a die substrate layer 220, 240,a front-end-of-line (FEOL) layer 218, 242, a (critical logic)back-end-of-line (BEOL) layer 214, 244, a partition/global BEOL layer212, and a custom BEOL layer 246. In certain embodiments, after beingdesignated as a supplementary IC in the manufacturing process, thesupplementary IC 150 can be equipped with a custom BEOL layer 246designed to facilitate connectivity between the supplementary IC 150 andthe primary IC 125. Consistent with various embodiments, the diesubstrate layer 220, 240, FEOL layer 218, 242, (critical logic) BEOLlayer 214, 244, partition/global BEOL layer 212, and custom BEOL layer246 can each be made up of one or more sub-layers of semiconductormaterials, interconnection devices, or other structures.

Aspects of the present disclosure relate to a 3D IC stack device with aprimary IC 125 and a supplementary IC 150 arranged in a back-to-frontorientation. In such a configuration, the partition/global BEOL layer212 of the primary IC 125 can be directly interfaced with the coolingelement. As the active devices (e.g. cores) located proximate to thepartition/global BEOL layer 212 of the primary IC 125 are a significantsource of heat for the IC stack device, placement next to the coolingelement can facilitate heat dissipation and thermal management of the ICstack device. Further, as the active devices located on the custom BEOLlayer 246 of the supplementary IC 150 can also generate heat, such aconfiguration with the custom BEOL layer 246 oriented facing the coolingelement can have further positive effects on the overall thermaldistribution of the IC stack device.

Aspects of the present disclosure are directed toward a 3D integratedcircuit stack device including one or more multiplexer blocks configuredto selectively route data between cores in the IC stack and a variety ofperipheral devices, such as an input/output ring, a power source, or adata pin. Other peripheral devices are also possible. In certainembodiments, both the primary IC 125 and the supplementary IC 150 caninclude a multiplexer block. In certain embodiments, the multiplexerblock 224 on the supplementary IC 150 can be unused, and the multiplexerblock 210 on the primary IC can function as the active multiplexer blockfor the IC stack device. For instance, in certain embodiments, themultiplexer block 210 can be communicatively connected with an enabledcore 102 on the supplementary IC and a disabled core 104 on the primaryIC 125, and selectively route data from the enabled core 102 to a databus in place of data from the disabled core 104.

Consistent with various embodiments, the primary IC 125 and thesupplementary IC 150 can include one or more TSV connections to allowfor communication between the supplementary IC 150 and the primary IC125. In certain embodiments, the primary IC 125 can include a TSV 202and a TSV 206, and the supplementary IC 150 can include a TSV 204. TheTSV 202 can be connected to the TSV 204 by means of a first chipinterconnect 230. Similarly, the TSV 206 can be connected to thesupplementary IC 150 by means of a second chip interconnect 232. Incertain embodiments, the multiplexer block 210 can be connected to theenabled core 102 through the TSV 206 and the second chip interconnect232. In certain embodiments, the multiplexer block 210 can be connectedto a peripheral component connection 228 (e.g., an input/output ring)through the TSV 202, the first chip interconnect 230, and the TSV 204.The multiplexer block 210 can also be communicatively connected with adata bus located on the primary IC 125.

FIG. 7 shows a block diagram of the process of assembling a 3Dintegrated circuit stack device, consistent with embodiments of thepresent disclosure. Consistent with various embodiments, the process canbegin with the preparation of silicon wafers at block 700. Waferpreparation can include the cutting and polishing of a slice from amono-crystalline ingot, as well as the process of pre-cleaning the waferwith high purity, low particle chemicals. In certain embodiments, thesilicon wafers can be heated and exposed to ultra-pure oxygen to form auniform-film silicon dioxide film on the surface of the wafer. Atcertain stages throughout the process described herein, the siliconwafers can undergo photolithography, or “masking.” In certainembodiments, a photo-resist or light-sensitive film can be applied tothe wafer, and the wafer can be aligned to a photomask pattern. Thewafer can then be exposed to high intensity light, transferring thegeometric pattern from the photomask to the silicon substrate.

The silicon wafer can then pass to block 704, at which point thefront-end-of-line (FEOL) devices can be formed. In certain embodiments,the FEOL devices can include transistors, capacitors, resistors andother discrete circuit components. At block 706, some of theback-end-of-line (BEOL) devices can be formed on the silicon wafer. Incertain embodiments, the BEOL devices can provide interconnections forthe FEOL devices already formed on the silicon wafer. In certainembodiments, the BEOL devices can include resistors, inductors,transmission lines, capacitors, wires, contacts, dielectrics, insulatorsor bonding sites.

At block 708, the wafers can undergo a partial device test. Thesemiconductor devices can be subjected to a variety of electrical teststo determine whether or not they are functioning properly. In certainembodiments, the silicon wafers can undergo kerf testing to monitor forfactors (e.g. defects in the kerf structures) that indicate likelihoodof cores on the wafer being defective or non-functional. For example, incertain embodiments, kerf testing can include testing of DRAM arrays,SRAM arrays, logic structures (e.g. latches and combinational logic) andother kerf structures. The results of the kerf testing can provideinformation about the health of a given silicon wafer, which can impactits path through the assembly process. In certain embodiments, if theresults of the kerf testing indicate that a silicon wafer has alikelihood beyond a certain tolerance level of cores on the wafer beingdefective, production of the entire wafer can be halted to avoid thecosts of further processing.

At block 710, the results of the kerf testing and/or partial devicetesting of block 708 can be used to classify a silicon wafer as aprimary based IC wafer or a supplementary based IC wafer. For example,consistent with various embodiments, wafers that were determined to besubstantially healthy by the kerf testing and/or partial device testingprocess can be classified as primary based IC wafers. In certainembodiments, wafers that were not determined to be substantially healthycan be classified as supplementary based IC wafers.

Based upon their classification as primary based IC wafers orsupplementary based IC wafers at block 710, the wafers can then proceedto either block 712 or block 714. If a wafer has been classified as aprimary based IC wafer it can proceed to block 714 to receive a finalBEOL layer. In certain embodiments, the final BEOL layer can includeadditional metal interconnection layers. In certain embodiments, if awafer has been classified as a supplementary based IC wafer, it canproceed to block 712 to receive a custom BEOL layer. The custom BEOLlayer can be unique with respect to the final BEOL layer of the primarybased IC wafer, and can facilitate connection between the enabled coreson the supplementary IC and the active data bus on the primary IC.

Further, blocks 712 and 714 can allow for the processing ofthrough-silicon-vias in the silicon wafers. In certain embodiments, oneor more TSVs can be created to allow for communication between thesupplementary IC and a primary IC or other peripheral component afterassembly of an IC stack device. In certain embodiments, thesupplementary based IC wafers can undergo TSV processing. In certainembodiments, both the supplementary based IC wafers and the primarybased IC wafers can undergo TSV processing.

The primary based IC wafers and the supplementary based IC wafers canthen pass to blocks 716 and 718, respectively, to undergo a final testto evaluate the functionality of the semiconductor devices. In certainembodiments, the final testing can be customized for the primary basedIC wafers and the supplementary based IC wafers due to the relativedifferences in their BEOL layers. In certain embodiments, the individualcores on a die can be tested to determine whether or not they arefunctioning properly. The cores on a die that are determined to benon-functional can be identified and disabled. For example, the locationof non-functional cores can be marked on the wafer using a drop of die.In certain embodiments, the non-functional cores can be physicallydisabled with a fuse, or logically disabled, such as through the use ofan EPROM logic switch. In certain embodiments, the location ofnon-functional or disabled cores on a given wafer can be logged to awafer map stored on a central computer database. This wafer map can thenbe used subsequently in block 724 and 726 for device categorization andassembly.

The primary based IC wafers and the supplementary based IC wafers canthen pass to blocks 720 and 722, respectively, to undergo wafer dicingand be cut into individual silicon die (i.e. primary ICs andsupplementary ICs). In certain embodiments, the dicing process can bebased upon the number and location of the enabled and disabled coresstored on the wafer map created in blocks 716 and 718.

After undergoing the dicing process, the primary ICs and thesupplementary ICs can then pass to blocks 724 and 726, respectively.Here, the individually cut silicon die can be categorized andrespectively sorted into one of a plurality of bins. In certainembodiments, primary ICs that have a full set of enabled cores, or“fully functional” die can pass directly to block 732 to undergomodule/build testing. In certain embodiments, the binning process of theprimary ICs and the supplementary ICs can be based upon the number andlocation of disabled cores on the primary IC and the supplementary IC.Accordingly, the wafer maps created in blocks 716 and 718 can bereferenced and used to sort the primary ICs and the supplementary ICs.For example, in certain embodiments, a supplementary IC could be sortedinto one of the bins A, B, C . . . N based upon a wafer map created inblock 716, and a primary IC could be sorted into one of the bins 1, 2, 3. . . N based upon a wafer map created in block 718.

At block 728, each primary IC can be matched with a supplementary IC. Incertain embodiments, the matching can be performed by using the wafermaps created in blocks 716 and 718 to pair each primary IC with asupplementary IC such that the location of one or more disabled cores onthe primary IC correspond to the location of an enabled core on thesupplementary IC. The primary IC and supplementary IC pairs can thenproceed to block 730, where they can be assembled into a chip stack. Incertain embodiments, the primary IC can undergo a back grinding processto reduce the thickness of the die substrate layer, and facilitatethermal management of the IC stack. For example, in certain embodiments,the supplementary IC and the primary IC can receive back-grinding aspart of the TSV creation process. Consistent with various embodiments,the primary IC can be communicatively connected to the supplementary IC,and equipped with an on-chip logic system configured to replace thefunctionality of disabled or non-functional cores on the primary IC withthe functionality of enabled cores from the supplementary IC. Theassembled IC stack devices can then proceed to block 732 for finalmodule/build testing to evaluate the functionality of the IC stackdevice as a whole. If they are determined to be functional, the IC stackdevices can then proceed to block 734 for final processing andpackaging.

Although the present disclosure has been described in terms of specificembodiments, it is anticipated that alterations and modificationsthereof will become apparent to those skilled in the art. Therefore, itis intended that the following claims be interpreted as covering allsuch alterations and modifications as fall within the true spirit andscope of the disclosure.

What is claimed is:
 1. A method of assembling an integrated circuit (IC)stack, comprising: testing, of a plurality of wafers each having aplurality of ICs, for factors indicative of the functionality of aplurality of cores located on each of the plurality of ICs;categorizing, as primary, a first subset of the plurality of wafersbased on the tested factors indicating that ICs of the first subset arelikely to have a ratio of enabled cores to disabled cores that isgreater than a threshold ratio; categorizing, as supplementary, a secondsubset of the plurality of wafers based on the tested factors indicatingthat ICs of the second subset are likely to have a ratio of enabledcores to disabled cores that is less than the threshold ratio; testing,for each IC of the plurality of ICs, functionality of the plurality ofcores located on the IC; identifying, based on results of the testing, asubset of the plurality of cores that have functional defects;disabling, in response to identifying the subset of the plurality ofcores, the subset of the plurality of cores; matching a first primaryIC, from the categorized primary wafers, with a first supplementary IC,from the categorized supplementary wafers; and assembling an IC stack ofthe first primary IC, the first supplementary IC, and a cooling element,such that the primary IC is between the cooling element and thesupplementary IC, the cooling element adapted to facilitate heatdissipation of the enabled cores of the primary and supplementary ICs.2. The method of claim 1, wherein the plurality of cores include one ormore microprocessors.
 3. The method of claim 1, wherein the matchingfurther comprises identifying the locations of the enabled cores anddisabled cores on the first primary IC and the first supplementary IC,comparing ICs from the first subset of wafers with ICs from the secondsubset of wafers, and pairing compared ICs such that the location of oneor more disabled cores of the one of the compared ICs corresponds to thelocation of an enabled core on another of the compared ICs.